POTW

[Phil Bondi]

..otherwise known as Puzzler Of The Week.

The complaint is:

with the una corda engaged, some hammers are hitting more 
than one note, and some hammers are getting hung up, mostly 
in the bass section.

Ok - multiple notes is pretty straight forward..well..not 
exactly:

As it turns out, the set screw for the Treble Cheek was set 
a bit too far back, towards the cavity, and when it hit the 
frame, that part of the frame was not square. The wood there 
angled to a 45º angle towards the action, which means, if 
you can picture this, the action was shifting ever so 
slightly from parallel when it hit the screw. Also, the 
guides? on the frame that go under the cheeks? - I'm 
sorry..I'm not sure of their name - those were not exactly 
close to where they needed to be, and both sides needed some 
TLC to keep them from rubbing on the cheek guides. Here's 
how that got fixed:

I changed the position of the screw 4 mil towards the keys, 
and made sure those guides? were not binding on either side 
of the cheek openings. I hope..that's a tough place to see.

OK - now I have the action going somewhat parallel from left 
to right, but there's a bunch of bass notes hanging up ever 
so slightly on the damper guide rail when I engage the una 
corda. The tenor and treble sections are now fine from the 
previous corrections..but those bass hammers..

I'll admit it probably took me an hr. to find the problem. 
With no cheek blocks in, the action moved just fine, albeit 
too far right, but the bass hammers did not hang up. As soon 
as I tightened both blocks, the offending bass hammers hung up.

What did I find?

-Phil Bondi(Fl)